Since I am using a mold there is probably not a lot of crossover.
If he does use the "band of epoxy where the seal tape" (another thread) he should cover everything from that band outward with blue painters tape. I put down my "tacky tape" and then cover it as well as most of the flange before I start the wet work. Then after everything is in the mold (glass, core, peel ply, release film, and breather) I pull up the blue tape and every thing is "dry" and clean.